This invention relates to a security system and, more particularly, to a system for controlling a lock which governs access to a locked area and for updating the lock code combination to be responsive to different inputted lock code combinations.
Various electronic lock systems employ a key card encoded with information in a binary code which is operable to open the lock if the lock is preset to be responsive to the code combination on the card. In such systems, a user inserts the card into a receptacle associated with the lock, and the lock circuitry actuates a bolt if the code combination stored in the lock is identical to the code combination inputted from the key card. These systems are particularly useful in buildings, such as hotels, which have large numbers of rooms which must be locked but where the identity of the person having authorized access changes from time to time. In addition, such systems can be used in other similar applications, such as for locking safe deposit boxes, automobiles, or rooms in a home or suite of offices.
These devices provide significant advantages over conventional lock systems. One of the primary advantages is the large number of code combinations which may be encoded on a card of relatively small size. In addition, mechanical lock systems are generally inflexible in that changing the locks or the combination of key settings is difficult and inconvenient. In mechanical lock systems in hotels and other large buildings, a key is required for each room and the presence of a large number of keys, each of which may be stolen, presents a security problem.
Some electronic systems using key cards have attempted to overcome the deficiencies of mechanical lock systems by employing a central control unit which is electrically connected to each of the many individual door locks. The central control unit remotely sets and changes the individual lock code combinations, senses the code combination on a key card inserted in the lock, and initiates some action at the remote door lock to unlock the door. One apparent disadvantage of such central systems is the susceptibility to failure of all locks if the central control unit is inoperable. In addition, electrically wiring all individual locks to a central control unit is expensive and often inconvenient, especially in older buildings.
In other electronic systems which do not employ central control units, the individual lock code combination in each door must be reset by manually changing switches or electrical connections before a new key card will operate the lock. This type of system requires a large expenditure of time to change lock code combinations in a facility having a large number of rooms, such as in a large hotel.
It is therefore desirable to provide a security system in which code combinations, stored in the lock, can be rapidly and conveniently changed. In addition, a secure means of encoding cards must be provided in order to ensure that employee misconduct in large facilities is kept to a minimum. For the same reason, it is also desirable to provide various levels of authorization to operate all or portions of the entire system. Finally, a secure back up system is necessary in the event of failure of the central encoding means.
One particular security system is disclosed by Sabsay in U.S. Pat. No. 3,821,704 issued June 28, 1974, and reissued as U.S. Pat. No. Re. 29,259 on June 7, 1977. In that patent, a central console or controller is provided for generating the key cards to be used in the various locks. More specifically, the security system disclosed by Sabsay includes a key card which has been encoded with a code combination in response to commands from a central console to generate either a new key card or a duplicate key card. Each code combination encoded on a key card has two fields. By contrast, only one field of a code combination is stored in the lock.
In operation, if the first field of the inputted code combination corresponds with the single field code combination stored in the lock, then the lock opens. No further comparisons are done with the second field of the inputted code combination. On the other hand, if the first field of the inputted code combination does not match, the single field code combination stored in the lock and the second field of the inputted code combination, are compared. If there is a positive comparison, the first field of the inputted code combination is stored in the lock thereby causing the code combination stored in the lock to be updated to correspond to the first field of the inputted code combination. It will, of course, be appreciated that the code combination inputted to the lock in the Sabsay system must be twice as long as the code combination stored in the lock.
By contrast, in the present invention both the inputted lock code combination and the stored lock code combinations have two fields. When the initial comparison is made, both fields are utilized and must correspond in order for the lock to be activated and opened.
While Sabsay provides a basic security system, there are many problems which apparently were not recognized. One such problem relates to synchronization between the central console and the various locks. More specifically, the code combination or combinations stored in each lock must also be stored in the central console so that the code combination of the particular lock for which a key card is to be generated, may be encoded upon that key card. Thus, the code combinations stored in the central console must be synchronized with the code combinations stored in the respective locks. The problem arises if sychronization is lost. Sabsay neither recognizes nor discloses any way of resynchronizing the lock and the central console memories. By contrast, the present invention provides a means whereby a lock code combination stored in the central console can be directly stored in any one of the alterable memories of the lock. More specifically, in the present invention a portable permanent security override module (PSOM) or a portable temporary security override module (TSOM) may be utilized to cause any lock code combination stored in either the PSOM or TSOM to be directly stored into the master memory, the station memory or the guest memory upon selection of a proper function using a function switch or dial on the PSOM or TSOM. Thus, an easy means of resynchronizing a lock to the console is provided. No such feature is even suggested by Sabsay.
Another problem which is neither addressed nor apparently recognized in Sabsay, is the problem of generating key cards or otherwise accessing a lock when the console fails. For example, the console may fail by having all code combinations in its memory lost. In such a situation the Sabsay system would be unable to generate new key cards capable of opening a lock. By contrast, if all code combinations in the memory are lost in the present system, the console is used to simply generate a new code combination for each lock and then using the portable PSOM or TSOM to transfer each new code combination, so generated for each lock, to the memory of that lock.
Furthermore, the console may be down and thus incapable of generating key cards. In the Sabsay system, if a guest lost his key card and thus required a duplicate key card, the console would be unable to make one, and the guest would be unable to enter his room until the console was repaired. By contrast, in the present invention either the PSOM or the TSOM can be utilized to open the lock directly without the need of a key card. In addition, the PSOM can be utilized to "program" a lock with a lock code combination from a pre-punched key card by inserting the key card into a PSOM reader which then loads the code combination into the selected lock memory. The key card is then given, for example, to the guest.
In this connection, it should also be noted that electronic locks can be provided with a lockout switch on the inside of the room to enable an occupant of the room to disable the lock from the inside thereby allowing additional security and privacy. If such a capability is provided in the Sabsay invention and the occupant becomes disabled or otherwise requires assistance in an emergency, access to the room would not be possible because the lock-out switch would have been activated. By contrast, in the present invention, the PSOM or TSOM may be utilized to override the lock out switch and directly open the lock without a key card.
Still another problem with the system disclosed by Sabsay is that the console may be accessed and duplicate keycards may be generated by anyone since there is no built in security system for the console. By contrast, the present invention provides that only a limited number of users will have access to the console.
More specifically, console access in the present invention is provided only upon insertion of an authorization card, similar in configuration to the key cards, into a console reader. Each authorization card has an authorization code combination stored thereon. In the preferred embodiment, upon insertion of the authorization card into the console's authorization card reader, the console is turned on and the authorization code combination compared against all authorization codes (generally numbering about 64) stored in one of the console memories. If correspondence with any of the stord authorization code combinations exists, then a processor in the console looks for a binary bit associated with that stored authorization code combination. If the binary bit has a specified value, then the authorization code combination is valid. If the authorization code combination is valid then the console remains on and hence is accessed. However, if the authorization code combination is invalid then the console will record the attempted transaction and will turn off the console thus preventing any further use of the console by the unauthorized user. The present invention also provides for various levels of authorization. For example, only a selected fraction of the valid authorization code combinations will be capable of using the console to generate a master key card.
Another feature of the present invention is the double lock switch which may be utilized to lock a selected lock from the outside. If the double lock switch is activated, the lock cannot be opened by any key card. Thus, the double lock capability provides a given room with additional security when the room is not occupied as, for example, where the room contains certain valuables which the absent occupant of the room seeks to protect. As previously mentioned, if the double lock is activated then only a PSOM or TSOM will be capable of unlocking the double lock. No such additional security is suggested or contemplated by the Sabsay system.
Finally, no means is disclosed in the Sabsay patent for correcting an operator error made in generating a new key card. For example, it may be that the console operator, in generating a new key card, inserts the wrong room number or other incorrect information into the console thereby causing a key card to be generated with an incorrect lock code combination. If such an error occurs, the console will have generated an inoperative key card and will have stored a new code combination in place of the old code combination for the selected lock without preserving the old code combination. By contrast, the present invention provides a means whereby a lock code combination which has been incorrectly generated and stored may be cancelled and the original or previously stored code combinations restored. Even if such a restore capability was not provided with the present invention, the PSOM or TSOM could be easily utilized to resynchronize a particular lock to whatever code combination had been generated and stored in the console.
Thus, it will be seen that the present invention has numerous advantages and features which were neither suggested nor disclosed by Sabsay.